Security devices, such as for example, padlocks and other types of conventional locks are known in the art. Many security devices are provided for restricting access to equipment and control instruments, including, for example, electrical components, such as switches, dials and push buttons, and fluid system components, such as valves and pressure regulators. One exemplary security device is a valve lockout device to prevent the operation of a valve, which may be utilized during maintenance of the associated fluid system or under other conditions in which the flow setting of the valve must not be changed.
Valve lockout devices typically restrict movement of the handle attached to a valve stem configured to actuate the valve. These devices generally use a feature to stop, resist, push, or pull against the body of the valve or the conduit attached directly to the valve. There are a number of issues that affect the versatility and functionality of designs of this type. Due to the large number of valve manufacturers and the wide variety of valve sizes, conduit sizes, valve body shapes and valve handle dimensions, the types of valves with which a single device design may be used is limited, requiring retention of several types or sizes of prior art valve lockout devices to accommodate the many types and sizes of valves in service at a typical plant. In addition, the installed position and location of the valve itself can vary. The orientation of the valve (vertical or horizontal) and the clearance of the valve from a wall, piping, or other pieces of equipment will affect the ability of a lockout device to be assembled with a valve.
Moreover, the handle is left attached to the valve in prior art designs. In certain designs, if a lever style handle is attached to a valve and the valve is locked out in any other position except open, the handle extends beyond the envelope of the valve body. In this condition, the valve becomes a moment arm that may be dislodged with sufficient force, compromising the locked out state of the valve.
Valves are primarily locked out for two reasons, for maintenance, or to maintain a necessary process. Because of the nature and methods employed by prior art and currently available devices, failure of these devices could potentially result in a hazardous, life threatening, or catastrophic situation.